Portable data collection devices are widely used in the manufacturing, service and package delivery industries to perform a variety of on-site data collection activities. Such portable data collection devices often include integrated bar code dataform readers adapted to read bar code dataforms affixed to products, product packaging and/or containers in warehouses, retail stores, shipping terminals, etc. for inventory control, tracking, production control and expediting, quality assurance and other purposes.
Bar code dataforms come in a variety of different formats including one and two dimensional bar codes, matrix codes and graphic codes, as well as words and numbers and other symbols, which may be printed or etched on paper, plastic cards and metallic and other items. For example, a one dimensional bar code dataform typically consists of a series of parallel light and dark rectangular areas of varying widths. The light areas are often referred to as “spaces” and the dark areas as “bars”. Different widths of bars and spaces define different characters in a particular bar code dataform.
Data originally encoded in a dataform is recovered for further use in a variety of ways. For example, a printed bar code may be illuminated to derive reflectance values which are digitized, stored in buffer memory and subsequently decoded to recover the data encoded in the bar code. The printed bar code may be illuminated using a laser, an array of LEDs, ambient light, or the like. The light reflected from the printed bar code typically is captured using a photosensor such as, for example, a CCD detector, CMOS detector, etc, which may take the form of a sensor array integrated circuit including a plurality of such device.
As data collection devices are used in more specialized applications, it is desirable to scan bar codes and other dataforms from different angles. Conventional scan engines include an image sensor component with an aperture adapted to receive incoming light from a scanned dataform. The light typically passes through an opening in the housing of the scan engine, and the housing may further include a protective cover for the opening. The trend in such devices is toward smaller and smaller packages, as a result of which it is desirable to reduce the size of the scan engine housing opening through which incoming light from a dataform enters. However, the image sensor components used in the data collection device scan engine may be too large to directly receive incoming light from a scanned dataform through a reduced size housing opening. Although the size of the aperture on such an image sensor may be reduced, the footprint of the integrated circuit on which the sensor aperture resides remains relatively large. Custom image sensor integrated circuits may be developed, however, it is desirable to use existing image sensor components to keep the data collection device scan engine cost low. Thus, there remains a need for a data collection device scan engine which may successfully scan dataforms from an angle using existing image sensor components through a reduced size housing opening, and which may scan bar code dataforms at an angle.